This method and apparatus are particularly useful for improving the extraction of products from extra cellular and intra cellular growth, especially for improving the extraction efficiency as to time and as to the quantity of material recovered. Various cells are grown in growth media with cellular products being extracted for use in various applications. Referring to FIG. 1, cells may be grown in containers having various shapes, with cells commonly grown in a growth flask or bio-reactor vessel 10 containing a growth media 12 and cellular material 36. One illustrative growth flask 10 is described in U.S. Pat. No. 7,381,559. If extra cellular growth is used the media 12 is selected to extract products 38 grown by and excreted through the cellular walls and into the media or otherwise extracted through the cellular walls and into the media, with subsequent processes separating the extracted products from the media and cells. If intra cellular growth is used, then a lysing agent is typically added to the media after growth is completed in order to rupture the cellular walls and allow the desired products to be separated from the media and ruptured cells in later processing. For either form of cellular growth, the process can be lengthy and result in product loss.
Still referring to FIG. 1, when growth is complete the fluid in the growth flask 10 is typically decanted into a storage container 14, sealed with cap 15 and can be stored until a sufficient quantity is collected for processing if the time permits, or if time is of the essence the fluid may be further processed immediately. Exemplary prior art means for transferring the contents of the flask 10 to a storage container or other container include the caps disclosed in U.S. Pat. Nos. 7,998,730 and 7,709,251
In decanting from the growth flask 10 to the storage container 14, the fluid may be transferred with or without filtering. The filtering seeks to separate the larger particles of the growth media and cells from the desired products and dissolved growth media which are smaller in size and pass through the filter. But some product is held by the filter or held by the debris collected on the upstream surface of the filter so that product is lost in the transfer. Typically, from about up to-20% of the product is lost in this filter step.
The material in the storage container 14, or from the growth flask 10, is ultimately placed in a centrifuge container 16 which uses centrifugal force from centrifuge 18 to separate the heavier cellular structures and larger particulate growth media from the desired product and dissolved growth media. The supernatant is removed from the centrifuge container 16 into a vacuum filter transfer flask 20. Because some of the product remains in the centrifuged cells and debris, about up to about 20% of the product is typically lost in the centrifuge separation. The vacuum filter transfer flask 20 has a neck with an opening that connects to a vacuum filter assembly 22 that is in fluid communication with a vacuum receptacle. 24. Negative pressure is applied to the downstream side of the filter assembly 22 so that the product is drawn through the filter assembly 22 and into the vacuum receptacle 24. The filter assembly is selected to allow the product to pass while restraining passage of the cells, cellular fragments, and growth media which are larger in size than the product. If the filter becomes clogged by debris, then the remaining volume of fluid material in the vacuum filter transfer flask 20 is passed through successive filter assemblies 22 until all of the product is filtered into one or more vacuum receptacles. Each time a vacuum filter assembly 22 is used about up to 10% of product is lost. The filtered fluid from the vacuum receptacle is then passed through a purification column, such as a Resin filled purification column 26 in order to bind the growth media to the column and allow the purified product 38 to be separated therefrom, with the resulting fluid product being used for various purposes depending on the nature of the product. The purification column 26 may be a sterile column. About up to about 20% of the product is lost in the purification column 26 to achieve the purified product 38 from the purification cartridge 26, separated from the growth media 12 and cellular material 36.
Since a portion of product is lost each time the fluid is processed since several processing steps are used to purify the product, the total amount of product lost (either in absolute terms or percentage terms) can be extensive. Further, each processing step introduces errors through spillage, handling, contamination, and other human or machine error involved with each process step. Since it can take large amounts of time to grow the cells and their products, and since the extraction and purification process is also time consuming, the resulting cost of obtaining purified products is high in terms of time, effort and money. There is thus a need for a more efficient method and apparatus to separate the cellular products from the remaining cells, cellular fragments, growth media, etc.
The prior art uses tangential-flow filters, microfiltration filters, centrifugation, depth filtration and sterile filtration to help “clarify” the fluid between the various process steps, as described in the article by D. Yavorsky, R. Blanck, C. Lambalot and R. Brunkow, The Clarification of Bioreactor Cell Cultures for Biopharmaceuticals, Pharmaceutical Technology, March 2003, pg. 62-76, available at www.pharmatec.com. But even the use of various filters and centrifuges results in numerous process steps during which product is lost. There is thus a need for a more efficient method and apparatus and system to separate the cellular products from the remaining cells, cellular fragments and particles other than the desired product. Moreover, every human intervention step adds error and there is thus a need for an improved method, apparatus and system that reduces the number of human handling steps and human intervention steps.